Believe it or not (or should we say ‘beliebe?’), yet more Justin Bieber Instagram photos out last week show the young mega-star in his underwear, plus Ashton Kutcher sags low and more Celebrity Underwear Sightings.

Oh, Justin. Look at you in what is likely your multi-million dollar private workout facility where they’re training you to be a ninja. Who are ‘they,’ exactly? It could be the government for all we know. In which case, we’re not sure they’ll jive with all the Instagram selfies you’ve taken to posting lately. But who cares what they think, we can’t get enough!

Also this week, Ashton Kutcher’s pants looked in danger of falling right off. Now, there’s someone who should be taking more underwear selfies, are we right?

Check out our full roundup of Celebrity Underwear Sightings and let us know if you’re jumping on the Instagram underwear selfie bandwagon. If only it were a real wagon…

Here’s another of JB, soon to be teen ruler of the free world:

Ashton, is that a water bottle in your pocket or are you just showing off?

Patrick Schwarzenegger shoots some hoops, giving us a glimpse of his waistband. Maybe he could take some pointers from Ashton on how to show us more off the goods next time?

Scottish rugby player and heartthrob Thom Evans sweat it out at Coachella in Palm Springs with his new love interest. We thought she might be his sister, but the heart shaped glasses really tipped us off. Hopefully the black undies beneath his red shorts are breathable enough to keep him cool!